1. Field of the Invention
The present invention relates to surveillance systems that issue alarm signals, and, more particularly, to reducing the issuance of false alarm signals by such surveillance systems.
2. Description of the Related Art
Surveillance systems, also known as security systems, include security devices such as motion detectors for monitoring interior portions of a secured area of space, and door sensors and window sensors for monitoring perimeter portions of the secured area of space. When one of these sensors detects motion and/or the opening of a monitored door or window, the security system may issue an alarm signal that causes a siren to produce an audible alarm, and that is electronically communicated to a security company. The security company typically notifies the police, who may then visit the secured area of space in order to investigate.
A problem is that many of the alarm signals issued by a security system are what are known as “false alarms”. False alarms are not the result of a genuinely dangerous condition, such as the presence of an intruder, but rather are a result of a resident of the building moving within the secured area of space and inadvertently causing an alarm signal to be issued. For example, a person returning home through their garage may enter through a side entry door of the garage that is monitored by the security system, or may open the side entry door to go outside after having driven into the garage through a garage door. Even if there is some time period provided by the security system to allow the resident to enter a passcode to thereby abort an alarm signal, the resident may not know, or may have forgotten, that the alarm system has been activated, and thus will not enter a passcode in time to prevent the occurrence of a false alarm. As another example, a resident may, without knowing or remembering that the alarm system has been activated, open a door in order to let a dog outside, or walk into a ground floor area that is monitored while the residents sleep on an upper floor. Again, even if the security system provides some audible or visual indication that a passcode needs to be provided in order to abort an alarm signal, the indication may not be of high enough intensity to get the attention of the resident, who may not be fully awake. The resulting audible alarm produced by a siren as a result of a false alarm often wakes many sleeping people needlessly. Moreover, investigations of the false alarms by the police are a waste of community resources and may result in the owners of the security system being monetarily fined.
An approach to reducing the false alarm problem is known as “entry delay”, in which some time period is provided by the security system to allow the resident to enter a passcode to thereby abort an alarm signal, as mentioned above. Most security systems employ an entry delay period which begins when the initial entry door is violated. The user needs to disarm the system within a programmed time period in order to avoid a false alarm. That is, if the system is not disarmed within the given time period, an alarm response will begin.
Another approach is known as “dialer delay”, which delays the sending of an alarm signal to a monitoring station for a predetermined time period. This gives the homeowner time to cancel the alarm before emergency service personnel are dispatched. The delay period begins when an alarm condition has been detected. The security system will delay the sending of an alarm signal to the central station for a programmed period of time. If the alarm condition is not acknowledged within the given time period, the security system will send a report to a central station.
A problem with both the entry delay and the dialer delay approach is that the resident of the secured building may not be aware that an alarm response is forthcoming, and that he needs to enter a passcode or take some other measure to prevent the alarm. A reason the resident may be unaware of the forthcoming alarm response is that he does not see or hear any indication from the security system that he needs to take action in order to avoid the alarm. Even if he does see and/or hear such an indication, the indication may not be of sufficient intensity to capture his attention and cause him to take action. Moreover, even if he does see and/or hear the indication, and it captures his attention, he may be too distracted, or may not be thinking clear enough, to comprehend the meaning or significance of the indication that he perceives.
A further problem is that even if the resident does see and/or hear an indication from the security system, the indication succeeds in capturing his attention, and he perceives its meaning, the indication does not inform the resident of how much time he has remaining to enter a passcode before it is too late to prevent an alarm response. Thus, it sometimes occurs that a resident overestimates an amount of time remaining to enter a passcode, and hence fails to enter the passcode within the allotted time, which results in a false alarm.
What is needed in the art is a security system, and method of operation therefor, that is capable of capturing a user's attention, regardless of where he is on the premises, and making the user aware that he needs to enter a passcode in order to prevent an alarm signal from being issued. What is also needed is a security system, and method of operation therefor, that provides a user with some indication of how much time is available for him to enter a passcode and thereby avoid the issuance of an alarm signal.